Game Balance Jehee Lee Seoul National University Game

Game Balance Jehee Lee Seoul National University

Game Balance • Beauty in balance • Game balance includes – Player/Player: Advantage in skill – Player/Gameplay: Learning curve matched by reward – Gameplay/Gameplay: Balance between features

Player/Player Balance • Ex) Virtua Fighter (Sega, 1993) – Say, there is someone who play as Sarah Bryant and can beat every other character. – Does it mean unbalanced? – What if beginner as Sarah can beat expert playing Lion? – What if player can choose from a range of characters?

Player/Player Balance • Victory by Skill and Judgment – There can be luck and gamble – Judging when to take risk can be part of fun • Avoid luck dominating gameplay • Symmetry is the fairest solution, but rarely the most interesting

Symmetry • Legends of Water Margin – – – – Two heroes square off for a duel Stand watching each other poised in kung fu stance Hours pass, days pass Then a breeze stirs up dust A speck goes in one hero’s eye He blinks, frowns, and suddenly relaxes with a sigh He bows to the other hero • Masters/Experts know result of duel without having to fight

Symmetry • No game should ever be decided by factor outside player’s control • Symmetrical at level of significant factors • Asymmetry is required for realism or aesthetics – Should be confined to minor factors – Should not sway outcome of game • Perfect symmetry works fine with abstract game • In real games, functional symmetry is more important – Units, levels, features

Intransitive Game Mechanics • Zero-sum game – Player’s gain/loss is exactly balanced by losses/gains of other players. – Payoff matrix (see blackboard) – Player assigns probabilities to their respective actions – Ex: Rock-Scissor-Paper • What if one player takes suboptimal strategy? – Ex: Rock (50%), Scissor (25%), Paper (25%)

Non-Zero-Sum Game • Prisoner’s Dillema – Two suspects are arrested and separated. – If one testifies against the other and the other remains silent, the defector goes free and the silent accomplice receives the full 10 -year sentence. – If both remain silent, both prisoners are sentenced to only six months in jail for a minor charge. – If each betrays the other, each receives a five-year sentence. – Each one is assured that the other would not know about the betrayal

Nash Equilbrium • Two or more players reach equilibrium, if – each player knows the equilibrium strategies of the other players – no player has anything to gain by changing only his or her own strategy unilaterally – If each player has chosen a strategy and no player can benefit by changing his or her strategy while the other players keep theirs unchanged • Not necessarily mean the best cumulative payoff

Player/Gameplay Balance • Frequent negative reviews for new games – – “Needless layers of complexity” “Makes you perform every last chore yourself” “Tasks are out of all proportion to onscreen rewards” “Tiresome and frustrating” • Balance – Not trivial, not too complex – Not too much labor, not too much automation

Case Study: Baldur’s Gate • Begin with the player having to randomly generate scores in attributes – Strength, dexterity, intelligence between 3 -18 • You can take points away from some traits and add them to others • You can REROLL to get a different set of values • If you are patient enough, you can get all 18’s

Player/Gameplay Balance • Balancing challenges against player’s improvement curve – Monsters get tougher with level – Widening options • Three rules – Reward the player – Let the machine do the work – Make a game that you player with, not against

Reward the Player • Player has to learn how to play – Mistakes are discouraging – Rewards for doing right offset discouragement • Ex) Virtua Fighter – It takes a while to learn tricky combinations – Sarah flip over her opponent (eye candy) – Elbow strike to the kidney (payoff) • Widening game experience – Ex) “Now with backflip, I can see new use for reverse punch” • In general, better to reward player for doing something right than punish for something wrong

Let the Machine do the Work • Question of the user interface • Blur of boundary between chore and game feature – For years, RPGs used to boxed with graph papers, so you could draw a map as you explored dungeons • If game option is no-brainer, consider AI talking care of it

Make a Game You Play with, Not Against • Games can be spoiled by insisting the progress by trial-and-error • Ex) crossbowman guarding the exit – Drink transparency portion. Sneak up. The guard sees and shoots you. Back to save. – Run up and attack. He is too fast. Back to save – Drop the bottle. He comes looking and shoots you. Back to save – Drink the portion and drop the empty portion. He walks by you for no reason. You finally escapes. • Should succeed by skill and judgment, not trial and error

Case Study: The Save Game Problem A designer talking about dungeon RPG A: “I’ve got a great trap. The player steps on platform, it descends into a chamber expecting full of treasure. Then, flamethrowers go off and he is toasted. ” B: “What if I jump off platform before it gets down” looking for a solution A: “we’ll have to make it a teleporter” seeing it a loophole B: “What is the solution? ” A: “There isn’t one! It’s a killer trap” B: “There is no clue before you teleport. Is it a good idea? ” A: “That’s what the Save feature is for. ”

The Save Game Problem • Save-Die-Reload cycle should not be a normal component of game experience • Beginner player should be able to reason and come up with answer – Challenges get tougher as game progress, but – It should balance with the player’s learning curve

Gameplay/Gameplay Balance • Challenges when balancing aspects of gameplay – Variety of interesting choices, rather than single dominant choice – Optimum choices depend on the choices other players make – How frequently different choices will be worth making • Two levels of balancing: Component and Attribute

Component Balance • Each choice reduced to a simple value relative to some other choice • Ex) pirate game – Dreadnoughts > Galleons > Brigantines – All have identical functions – If Dreadnoughts 2 x powerful, then Galleons should take ½ time to spawn – If Brigantines 2 x speed, how can we weigh speed against power? – What if Galleons can attack flying units while the others cannot?

Attribute Balancing • Involves not the relative values, but the way the choices interact – Assessing how important each attribute will be as opposed to other attributes – such as speed, firepower, upgradability, range, and so on) • Use simple concepts to make first guess, then lots of play testing to fine tune • Attribute balancing harder to get right than component balance

Combinatorial Explorsions • How many attributes should you include to make interesting? – N factors leads to 2^n possible combinations “In Populous, should have lots of character types or only a half-dozen? I would be easier to understand the game experience with a few, very versatile units rather than many specific ones. ” - Richard Leinfellner, Executive in Charge of Production at Bullfrog

Design Scalability • Intransitive relationships are inflexible to alter – If we remove one component, some component may dominate • Relatively easy to add components • If you are going to scale, plan to scale up, not down